Molecules

24 pages, 19669 KiB

Open AccessArticle

Experimental and Mechanistic Study on Flotation Separation of Chalcopyrite and Molybdenite Using the Novel Depressant 2-Mercapto-6-Methylpyrimidin-4-ol

by Xiangwen Lv, Anruo Luo, Xiong Tong, Jianhua Chen and Sheng Jian

Molecules 2025, 30(6), 1396; https://doi.org/10.3390/molecules30061396 - 20 Mar 2025

Cited by 1 | Viewed by 514

Abstract

Chalcopyrite and molybdenite are vital strategic metal resources. Due to their close association in ores, flotation methods are commonly used for separation. The flotation separation method primarily employs the “copper depression and molybdenum flotation” process, enhancing the wettability difference between chalcopyrite and molybdenite [...] Read more.

Chalcopyrite and molybdenite are vital strategic metal resources. Due to their close association in ores, flotation methods are commonly used for separation. The flotation separation method primarily employs the “copper depression and molybdenum flotation” process, enhancing the wettability difference between chalcopyrite and molybdenite through a chalcopyrite depressant. Traditional depressants often face challenges, including low selectivity, high dosage requirements, poor stability, and significant environmental pollution, highlighting the need for new, highly selective green reagents. This study introduces the novel chalcopyrite depressant 2-mercapto-6-methylpyrimidin-4-ol (MMO) for flotation separation. The influence of MMO on chalcopyrite and molybdenite flotation recovery was examined through microflotation experiments. Additionally, the effects of MMO and ethyl xanthate on surface wettability were assessed via contact angle measurements. The adsorption microstructure and interaction mechanism of MMO on chalcopyrite were elucidated using FT-IR, TOF-SIMS, and XPS analyses and DFT simulations. Results indicate that MMO enhances chalcopyrite hydrophilicity and exhibits a strong depressing effect on its flotation, while minimally impacting molybdenite recovery. Thus, it serves as an effective depressant. During adsorption, N and S atoms in MMO donate electrons to Fe and Cu ions, leading to triple bond adsorption and a stable chelate structure. These findings are crucial for achieving a greener and more efficient flotation separation of copper and molybdenum. Full article

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12 pages, 699 KiB

Open AccessArticle

Large Enhancement of the Luminescence Properties of an Eu(III) Dye upon Association with the DNA-CTMA Matrix

by Daniele Marinotto, Cosmina Andreea Marin, Ileana Rau, Alessia Colombo, Francesco Fagnani, Dominique Roberto and Claudia Dragonetti

Molecules 2025, 30(6), 1395; https://doi.org/10.3390/molecules30061395 - 20 Mar 2025

Viewed by 315

Abstract

In this study, the photophysical properties of thin films of an Eu³⁺ dye, namely europium tetrakis(dibenzoylmethide) triethylammonium (EuD₄TEA), within deoxyribonucleic acid (DNA) biopolymer functionalized with hexadecyltrimethylammonium chloride (CTMA) were extensively investigated and compared with those of thin films of the [...] Read more.

In this study, the photophysical properties of thin films of an Eu³⁺ dye, namely europium tetrakis(dibenzoylmethide) triethylammonium (EuD₄TEA), within deoxyribonucleic acid (DNA) biopolymer functionalized with hexadecyltrimethylammonium chloride (CTMA) were extensively investigated and compared with those of thin films of the same dye embedded in more conventional polymers, like poly(methyl methacrylate) and polycarbonate. The new materials obtained have good optical properties, as shown by their absorption and emission spectra. Remarkably, a large enhancement in photoluminescence was observed upon the interaction of EuD₄TEA with DNA-CTMA (2- and 17-fold increase in luminescence quantum yield with respect to PMMA and PC). Photophysical analyses suggest that the emission enhancement was mainly due to the increase in the sensitization efficiency (η_sens) from the ligands to the Eu³⁺ ion along with the suppression of the vibrational deactivation upon immobilization onto the DNA-CTMA matrix, as the concentration of the complex increased from 20 to 50%. These phenomena are primarily driven by the transformation of the Eu³⁺ micro-environments, which are created by the interactions between complex ligands and the DNA-CTMA matrix. Full article

(This article belongs to the Special Issue 30th Anniversary of Molecules: Recent Advances in Photochemistry)

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12 pages, 2131 KiB

Open AccessArticle

Anti-Glycation Activities of Angelica keiskei Leaves

by Yuno Takemoto, Takashi Kikuchi, Wenjun Qi, Mi Zhang, Kouharu Otsuki and Wei Li

Molecules 2025, 30(6), 1394; https://doi.org/10.3390/molecules30061394 - 20 Mar 2025

Viewed by 427

Abstract

The screening of a small library of Japanese herbal tea extracts revealed significant anti-glycation activity in the leaves of Angelica keiskei. LC-MS analysis led to the identification of twenty compounds in this herb tea, including seven flavonoids, five phenylpropanoids, and eight coumarin [...] Read more.

The screening of a small library of Japanese herbal tea extracts revealed significant anti-glycation activity in the leaves of Angelica keiskei. LC-MS analysis led to the identification of twenty compounds in this herb tea, including seven flavonoids, five phenylpropanoids, and eight coumarin derivatives, based on their chromatographic behavior and fragmentation patterns. Further LC-MS analysis of the methanol-eluted fraction after incubation with methylglyoxal (MGO) was performed on the reaction mixture, revealing quercetin 3-O-glucoside to be a key compound contributing to the anti-glycation activity of the leaves. Full article

(This article belongs to the Special Issue Biological Activity of Plant Extracts)

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18 pages, 4124 KiB

Open AccessArticle

Polythiophene/Ti₃C₂T_X MXene Composites for Effective Removal of Diverse Organic Dyes via Complementary Activity of Adsorption and Photodegradation

by Young-Hwan Bae, Seongin Hong and Jin-Seo Noh

Molecules 2025, 30(6), 1393; https://doi.org/10.3390/molecules30061393 - 20 Mar 2025

Viewed by 363

Abstract

This study presents an effective method to remove organic dyes from wastewater, using a composite of few-layered porous (FLP) Ti₃C₂T_x MXene and polythiophene (PTh) nanospheres. The FLP MXene, which was pre-synthesized by a series of intercalation, heat-induced TiO [...] Read more.

This study presents an effective method to remove organic dyes from wastewater, using a composite of few-layered porous (FLP) Ti₃C₂T_x MXene and polythiophene (PTh) nanospheres. The FLP MXene, which was pre-synthesized by a series of intercalation, heat-induced TiO₂ formation, and its selective etching, was combined with PTh nanospheres via a simple solution method. The composite effectively removed various organic dyes, but its efficiency was altered depending on the type of dye. Particularly, the removal efficiency of methylene blue reached 91.3% and 97.8% after irradiation for 10 min and 1 h, respectively. The high dye removal efficiency was attributed to the large surface area (32.01 m²/g) of the composite, strong electrostatic interaction between the composite and dye molecules, and active photodegradation process. The strong electrostatic interaction and large surface area could facilitate the adsorption of dye molecules, while photocatalytic activity further enhance dye removal under light. These results are indicative that the PTh/FLP MXene composite may be a promising material for environmental remediation through synergistic processes of adsorption and photocatalysis. Full article

(This article belongs to the Special Issue Heterogeneous Catalysis for Sustainability and Carbon-Neutrality)

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18 pages, 1626 KiB

Open AccessReview

Potential of Bio-Sourced Oligogalacturonides in Crop Protection

by Camille Carton, Maryline Magnin-Robert, Béatrice Randoux, Corinne Pau-Roblot and Anissa Lounès-Hadj Sahraoui

Molecules 2025, 30(6), 1392; https://doi.org/10.3390/molecules30061392 - 20 Mar 2025

Viewed by 511

Abstract

During plant development or interactions with pathogens, modifications of the plant cell wall occur. Among the enzymes involved, pectinases, particularly polygalacturonases (PGases), play a crucial role in the controlled hydrolysis of cell wall polysaccharides, leading to the formation of oligogalacturonides (OGs). These pectin-derived [...] Read more.

During plant development or interactions with pathogens, modifications of the plant cell wall occur. Among the enzymes involved, pectinases, particularly polygalacturonases (PGases), play a crucial role in the controlled hydrolysis of cell wall polysaccharides, leading to the formation of oligogalacturonides (OGs). These pectin-derived fragments act as key elicitors of plant defense responses, stimulating innate immunity and enhancing resistance to pathogens by modulating the expression of genes involved in immune responses and inducing the production of defense compounds. OGs are of particular interest for plant protection as a natural alternative to conventional phytosanitary products as they can be obtained through chemical, thermal, or enzymatic degradation of plant biomass. In a sustainable approach, agricultural by-products rich in pectin, such as citrus peels, apple pomace, or sugar beet pulp, offer an eco-friendly and cost-effective alternative for OG production. Thus, the current review aims to (i) update the state of the art about the different methods used to produce OGs, (ii) explore the potential of OGs as bio-based biocontrol molecules, and (iii) examine the relevance of new pectin sources for OG production. Full article

(This article belongs to the Special Issue Chitosan, Chitosan Derivatives, Polysaccharides and Their Applications—2nd Edition)

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20 pages, 1348 KiB

Open AccessArticle

Recovery of Natural Hypoglycemic Compounds from Industrial Distillation Wastewater of Lamiaceae

by Claudia Sciacca, Nunzio Cardullo, Martina Savitteri, Maria Gaetana Giovanna Pittalà, Luana Pulvirenti, Edoardo Marco Napoli and Vera Muccilli

Molecules 2025, 30(6), 1391; https://doi.org/10.3390/molecules30061391 - 20 Mar 2025

Viewed by 338

Abstract

The food industry generates the largest number of valuable by-products. The recovery of compounds such as fatty acids and polyphenols with notorious biological properties from biowaste is a new challenge in the circular economy scenario, as they represent value-added starting materials for the [...] Read more.

The food industry generates the largest number of valuable by-products. The recovery of compounds such as fatty acids and polyphenols with notorious biological properties from biowaste is a new challenge in the circular economy scenario, as they represent value-added starting materials for the preparation of functional foods, food supplements, cosmetics and over-the-counter drugs. Less commonly explored are industrial wastewaters, which return to the nearby water streams without adequate treatment. Distillation wastewater (DWW) from the essential oils or agro-food industries may represent a valuable source of bioactive compounds to be valorized. In this work, DWW from rosemary was treated with different resins through dynamic and static adsorption/desorption approaches, for the recovery of phenolic compounds including rosmarinic acid. The most effective methodology, selected according to total phenolic and rosmarinic acid contents, as well as antioxidant activity evaluation, was applied to sage, thyme and oregano DWWs. The procedure provides several advantages compared with conventional separation processes, as it involves the lower consumption of reagents/solvents, low operational costs, ease of handling, and simplicity of scale-up. The results of this work highlight a fast and sustainable procedure for the recovery of rosmarinic acid and other phenolics (caffeic acid derivatives and flavonoid glycosides) from DWWS, thus affording a fraction with antioxidant and hypoglycemic activities. Full article

(This article belongs to the Special Issue Recent Advances in the Valorization of Food, Agricultural By-Products and Waste, 2nd Edition)

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16 pages, 1277 KiB

Open AccessArticle

Fatty Acid Enrichment of Corn Extrudates with Hemp Seeds

by Marta Igual, David Gimeno, Purificación García-Segovia, Javier Martínez-Monzó and Juliana Navarro-Rocha

Molecules 2025, 30(6), 1390; https://doi.org/10.3390/molecules30061390 - 20 Mar 2025

Viewed by 466

Abstract

Hemp seeds (HSs) are a rich source of essential fatty acids, proteins, and antioxidant compounds, making them an attractive ingredient for the food industry. This work studies the viability of enriching corn extrudates with hemp seeds, specifically to improve their fatty acid profile [...] Read more.

Hemp seeds (HSs) are a rich source of essential fatty acids, proteins, and antioxidant compounds, making them an attractive ingredient for the food industry. This work studies the viability of enriching corn extrudates with hemp seeds, specifically to improve their fatty acid profile and phenolic content, thereby enhancing the nutritional value of the snack. Extrudate formulations with different concentrations of HSs (up to 12.5%) were evaluated, and the physicochemical, textural, and antioxidant properties of the resulting products were analyzed. The results showed that increasing the HS concentration improved the lipid profile of the products, raising the content of unsaturated fatty acids to 75.6% in the snack fortified with 12.5% of HSs and lowering the proportion of saturated fatty acids. This may reduce the risk of cardiovascular diseases compared with corn extrudates. The total phenolic content of the snacks and their antioxidant capacity also increased linearly with the increase of HSs in the formulation. A reduction in specific mechanical energy during extrusion was also observed, attributed to the higher fat content, which facilitates the lubrication of the process. At the physicochemical level, the HS-enriched snacks showed improvements in texture. These snacks were softer, reducing the hardness of the corn snack while maintaining crunchiness. They were even more stable due to a lower water content. The fortification of snacks with hemp seeds provides consumers with a healthier option, while maintaining the appealing crunchy texture and visual appearance regardless of some changes in their color attributes. Full article

(This article belongs to the Special Issue Plant Foods Ingredients as Functional Foods and Nutraceuticals III)

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24 pages, 5269 KiB

Open AccessArticle

Hydrogenated Planar Aluminum Clusters: A Density Functional Theory Study

by Changhong Yao, Meijiao Wang and Lianzhen Cao

Molecules 2025, 30(6), 1389; https://doi.org/10.3390/molecules30061389 - 20 Mar 2025

Viewed by 322

Abstract

The low-lying energy structures of small planar aluminum clusters Al_n (n = 3–6, 8–10), hydrogenated small planar aluminum clusters Al_nH_m (n = 3–8, m = 1–2) and the lowest-energy structure of Al_nH_m (n = 6–10, m [...] Read more.

The low-lying energy structures of small planar aluminum clusters Al_n (n = 3–6, 8–10), hydrogenated small planar aluminum clusters Al_nH_m (n = 3–8, m = 1–2) and the lowest-energy structure of Al_nH_m (n = 6–10, m = 0–2) are determined by density functional theory (DFT) calculations. Many stable planar structures have been found; some are consistent with the reported ones, and some are new configurations. The preservation of planar cluster structures has been observed during the dissociative adsorption of H₂.Hydrogen is adsorbed at different positions on planar aluminum clusters. Dissociative adsorption configurations of the planar structure and lowest-energy structure experienced a decrease in hydrogen adsorption energy with an increase in cluster size. Among the clusters we calculated, Al₄H₁ and Al₄H₂ have the highest HOMO-LUMO gap, indicating that they may be more abundant than other clusters. The geometric structure and electronic properties of these clusters are also discussed. Full article

(This article belongs to the Special Issue Quantum Chemical Calculations of Molecular Reaction Processes)

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21 pages, 2137 KiB

Open AccessArticle

New Insights into the Metabolic Profile and Cytotoxic Activity of Kigelia africana Stem Bark

by Dimitrina Zheleva-Dimitrova, Rositsa Mihaylova, Maria Nikolova, Nisha Singh and Spiro Konstantinov

Molecules 2025, 30(6), 1388; https://doi.org/10.3390/molecules30061388 - 20 Mar 2025

Viewed by 449

Abstract

Ultra-high-performance liquid chromatography coupled to Orbitrap high-resolution mass spectrometry (UHPLC-HRMS) was recently employed in many fields to obtain a rapid characterization of plant extracts. Kigelia africana (family Bignoniaceae) is a quintessential African herbal medicinal plant with immense indigenous medicinal and non-medicinal applications. The [...] Read more.

Ultra-high-performance liquid chromatography coupled to Orbitrap high-resolution mass spectrometry (UHPLC-HRMS) was recently employed in many fields to obtain a rapid characterization of plant extracts. Kigelia africana (family Bignoniaceae) is a quintessential African herbal medicinal plant with immense indigenous medicinal and non-medicinal applications. The aim of the present research was to obtain an in-depth metabolite profiling of the K. africana stem bark extract using UHPLC-HRMS and to conduct a preliminary screening of its anticancer activity against a panel of malignant human cell lines of different origin. The UHPLC-HRMS analysis revealed 63 secondary metabolites including phenolic acids, gallo- and ellagitannins, iridoids, naphthoquinones, and anthraquinones. A total of 34 of all annotated compounds are reported for the first time in K. africana stem bark. The studied profile was dominated by trimethylellagic acid, dimethylellagic acid isomers, and ellagic acid. In all tumor models, we established a pronounced inhibition of cell growth in a mostly dose-dependent manner, with IC₅₀ values ranging near and well below (4–30 µg/mL) the lowest treatment concentration of 25 µg/mL. The established cytotoxicity profile of the K. africana extract, highly biased toward malignantly transformed but not normal cells, suggests specific modulation of defined molecular tumor targets. This study revealed K. africana stem bark as a new source of gallo- and ellagitannins, and highlighted the studied herbal drug as an antiproliferative agent with potential pharmaceutical application. Full article

(This article belongs to the Special Issue Extraction, Characterization, and Potential Applications of Bioactive Molecules from Natural Sources, 4th Edition)

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16 pages, 7631 KiB

Open AccessArticle

The Effect of the Ratio of Butylene Succinate and Dilinoleic Diol in Their Copolyester (PBS-DLS) on the Physicochemical Properties and Biofilm Formation

by Szymon Macieja, Agnieszka Piegat, Małgorzata Mizielińska, Nina Stefaniak, Mirosława El Fray, Artur Bartkowiak and Magdalena Zdanowicz

Molecules 2025, 30(6), 1387; https://doi.org/10.3390/molecules30061387 - 20 Mar 2025

Viewed by 360

Abstract

Biofilm-forming microorganisms pose a severe threat in the food and medical industries, among others. In this paper, the research materials were poly(butylene succinate–dilinoleic succinate) (PBS–DLS) copolymers with variable hard and soft segment weight ratios (90:10, 70:30, and 50:50). Polymeric films were prepared by [...] Read more.

Biofilm-forming microorganisms pose a severe threat in the food and medical industries, among others. In this paper, the research materials were poly(butylene succinate–dilinoleic succinate) (PBS–DLS) copolymers with variable hard and soft segment weight ratios (90:10, 70:30, and 50:50). Polymeric films were prepared by the solvent casting method. Selected physicochemical properties and the tendency to form biofilm on the polymer surface were investigated. As the amount of DLS soft segments in the polymer matrix increased, changes in the FTIR–ATR spectra (signal intensity), surface (SEM), and phase transition (DSC) were observed. The higher the content of the DLS segment, the lower the transition temperatures and the smoother the film’s surface. These factors resulted in a significant reduction in the amount of biofilm formed on the material’s surface and a decrease in the metabolic activity of microorganisms present in the biofilm and SEM micrographs. The obtained PBS–DLS films have great potential in the food and medical packaging industries. Full article

(This article belongs to the Special Issue Development of Food Packaging Materials)

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12 pages, 7602 KiB

Open AccessArticle

Structural Insights into Salinosporamide a Mediated Inhibition of the Human 20S Proteasome

by Hagen Sülzen, Pavla Fajtova, Anthony J. O’Donoghue, Jan Silhan and Evzen Boura

Molecules 2025, 30(6), 1386; https://doi.org/10.3390/molecules30061386 - 20 Mar 2025

Viewed by 472

Abstract

The 20S proteasome, a critical component of the ubiquitin–proteasome system, plays a central role in regulating protein degradation in eukaryotic cells. Marizomib (MZB), also known as salinosporamide A, is a natural γ-lactam-β-lactone compound derived from Salinispora tropica and is a potent 20S proteasome [...] Read more.

The 20S proteasome, a critical component of the ubiquitin–proteasome system, plays a central role in regulating protein degradation in eukaryotic cells. Marizomib (MZB), also known as salinosporamide A, is a natural γ-lactam-β-lactone compound derived from Salinispora tropica and is a potent 20S proteasome covalent inhibitor with demonstrated anticancer properties. Its broad-spectrum inhibition of all three proteasome subunits and its ability to cross the blood–brain barrier has made it a promising therapeutic candidate for glioblastoma. In addition to this, MZB also demonstrates significant inhibition against the 20S proteasome of Trichomonas vaginalis (Tv20S), a protozoan parasite, suggesting its potential for parasitic treatments. Here, we present the cryo-EM structure of the human 20S proteasome in complex with MZB at 2.55 Å resolution. This structure reveals the binding mode of MZB to all six catalytic subunits within the two β-rings of the 20S proteasome, providing a detailed molecular understanding of its irreversible inhibitory mechanism. These findings enhance the therapeutic potential of MZB for both cancer and parasitic diseases at the molecular level and highlight marine-derived natural products in targeting the proteasome for therapeutic applications. Full article

(This article belongs to the Special Issue Small-Molecule Modulators Targeting Emerging Therapeutic Pathways: Design, Synthesis and Biological Evaluation)

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31 pages, 9219 KiB

Open AccessArticle

Performance Optimization of SiO_2f/SiO₂ Composites Derived from Polysiloxane Ceramic Precursors

by Xia Zhang, Bo Xiao, Yongzhao Hou and Guangwu Wen

Molecules 2025, 30(6), 1385; https://doi.org/10.3390/molecules30061385 - 20 Mar 2025

Viewed by 391

Abstract

In this paper, polymethylhydrosiloxane (PMHS) and ethanol were used as raw materials to synthesize the ceramic precursor of side ethoxy polysiloxane (PESO) using dehydration and a dealcoholization reaction, which had a ceramic yield of 87.15% and a very low residual carbon content. With [...] Read more.

In this paper, polymethylhydrosiloxane (PMHS) and ethanol were used as raw materials to synthesize the ceramic precursor of side ethoxy polysiloxane (PESO) using dehydration and a dealcoholization reaction, which had a ceramic yield of 87.15% and a very low residual carbon content. With the quartz fiber as a reinforcer, the silica matrix composites (SiO_2f/SiO₂) with a double-layer interface (PyC-SiO₂/BNNSs) coating were manufactured using precursor impregnation pyrolysis (PIP). The as-prepared SiO_2f/SiO₂ possessed an excellent mechanical property, which exhibited obvious fiber pull-out and debonding phenomena from a fracture morphology. The flexural strength and fracture toughness of SiO_2f/SiO₂ reached 63.3 MPa and 2.52 MPa·m^1/2, respectively. Moreover, the SiO_2f/SiO₂ had suitable dielectric properties, with a dielectric constant of about 2.5 and a dielectric loss of less than 0.01. This work provides an important concept for the enhancement of the dielectric properties and mechanical properties of quartz fiber-reinforced ceramic matrix composites, as well as in the preparation of wave-transmissivity composites. Full article

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22 pages, 6822 KiB

Open AccessArticle

The Proteomic Analysis of Platelet Extracellular Vesicles in Diabetic Patients by nanoLC-MALDI-MS/MS and nanoLC-TIMS-MS/MS

by Joanna Kasprzyk-Pochopień, Agnieszka Kamińska, Przemysław Mielczarek, Radosław Porada, Ewa Stępień and Wojciech Piekoszewski

Molecules 2025, 30(6), 1384; https://doi.org/10.3390/molecules30061384 - 20 Mar 2025

Viewed by 526

Abstract

Platelet extracellular vesicles (PEVs) are emerging as key biomarkers in diabetes mellitus (DM), reflecting altered platelet function and coagulation pathways. This study compares two proteomic techniques—nanoLC-MALDI-MS/MS and nanoLC-TIMS-MS/MS—for analyzing PEVs in diabetic patients, to assess their potential for biomarker discovery. PEVs were isolated [...] Read more.

Platelet extracellular vesicles (PEVs) are emerging as key biomarkers in diabetes mellitus (DM), reflecting altered platelet function and coagulation pathways. This study compares two proteomic techniques—nanoLC-MALDI-MS/MS and nanoLC-TIMS-MS/MS—for analyzing PEVs in diabetic patients, to assess their potential for biomarker discovery. PEVs were isolated from platelet-rich plasma and characterized using tunable resistive pulse sensing (TRPS), Fourier-transform infrared (FTIR) spectroscopy, and transmission electron microscopy (TEM). Proteomic analyses identified significant differences in protein expression between diabetic and non-diabetic individuals, with nanoLC-TIMS-MS/MS demonstrating superior sensitivity by detecting 97% more unique proteins than nanoLC-MALDI-MS/MS. Key differentially expressed proteins included apolipoproteins and oxidative stress markers, which may contribute to platelet dysfunction and cardiovascular complications in DM. Sex-specific variations in protein expression were also observed, highlighting potential differences in disease progression between male and female patients. The integration of advanced proteomic methodologies provides novel insights into the role of PEVs in diabetes pathophysiology, underscoring their diagnostic and therapeutic potential. These findings pave the way for improved biomarker-based strategies for early detection and monitoring of diabetic complications. Full article

(This article belongs to the Special Issue Recent Advances in Mass Spectrometry Analysis for Medical and Pharmaceutical Applications)

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19 pages, 4595 KiB

Open AccessArticle

Preparation and Characterization of Biocomposite Films with Enhanced Oxygen Barrier and Antioxidant Properties Based on Polylactide and Extracts from Coffee Silverskin

by Argyri-Ioanna Petaloti, Adamantini Paraskevopoulou and Dimitris S. Achilias

Molecules 2025, 30(6), 1383; https://doi.org/10.3390/molecules30061383 - 20 Mar 2025

Viewed by 498

Abstract

In the food packaging industry, significant efforts have been dedicated to addressing the pressing market demand for environmentally friendly and sustainable products. Biocomposite films based on compostable and biobased polymers represent a sustainable alternative to conventional packaging materials, offering biodegradability and enhanced functional [...] Read more.

In the food packaging industry, significant efforts have been dedicated to addressing the pressing market demand for environmentally friendly and sustainable products. Biocomposite films based on compostable and biobased polymers represent a sustainable alternative to conventional packaging materials, offering biodegradability and enhanced functional properties. Additionally, there is growing interest in utilizing waste materials from agriculture and the food industry. This study focuses on the development of multifunctional eco-sustainable biocomposite films by combining poly(lactic acid) (PLA) as a biopolymeric matrix and extracts derived from coffee silverskin (CS), a significant agro-industrial waste byproduct of the coffee roasting process. Extracts of coffee silverskin were obtained via extraction with several solvents. Several properties of the prepared biocomposites were measured using techniques such as scanning electron microscopy (SEM), infrared spectroscopy (FTIR, ATR), differential scanning calorimetry (DSC), and oxygen and water vapor permeability, together with mechanical and physico-chemical characterization and measurements of water content, film solubility, and degree of swelling. The results demonstrate that optimized formulations of PLA/CS biocomposite films exhibit enhanced oxygen barrier properties, reduced permeability, and significant antioxidant activity. These findings underscore the potential for agro-waste valorization in creating eco-friendly food packaging solutions. Full article

(This article belongs to the Special Issue 30th Anniversary of Molecules—Recent Developments in Biobased Polymers)

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13 pages, 2686 KiB

Open AccessArticle

Development of Layer-by-Layer Magnetic Nanoparticles for Application to Radiotherapy of Pancreatic Cancer

by Nobuyoshi Fukumitsu, Yoshitaka Matsumoto, Lili Chen, Yu Sugawara, Nanami Fujisawa, Eri Niiyama, Sosuke Ouchi, Emiho Oe, Takashi Saito and Mitsuhiro Ebara

Molecules 2025, 30(6), 1382; https://doi.org/10.3390/molecules30061382 - 20 Mar 2025

Viewed by 477

Abstract

Pancreatic cancer is among the deadliest malignancies, with few treatment options for locally advanced, unresectable cases. Conventional therapies, such as chemoradiotherapy and hyperthermia, show promise but face challenges in improving outcomes. This study introduces a novel drug delivery system using gemcitabine (GEM)-loaded layer-by-layer [...] Read more.

Pancreatic cancer is among the deadliest malignancies, with few treatment options for locally advanced, unresectable cases. Conventional therapies, such as chemoradiotherapy and hyperthermia, show promise but face challenges in improving outcomes. This study introduces a novel drug delivery system using gemcitabine (GEM)-loaded layer-by-layer magnetic nanoparticles (LBL MNPs) combined with alternating magnetic field (AMF) application and X-ray irradiation to enhance therapeutic efficacy. LBL MNPs were synthesized using optimized layering techniques to achieve superior drug loading and controlled release. Human pancreatic cancer cells (PANC-1) were treated with LBL MNPs alone, with AMF-induced hyperthermia, and in combination with X-rays. The results demonstrate that the 7-layer LBL MNPs exhibited optimal cytotoxicity, significantly reducing cell viability at concentrations of 30 µg/mL and higher. Combining 7-layer LBL MNPs with AMF increased cell death in a time- and concentration-dependent manner, achieving up to 98% inhibition of cell proliferation. The addition of X-rays to the regimen demonstrated a strong synergistic effect, resulting in a 13-fold increase in cell death compared to controls. These findings highlight the potential of this integrated approach to improve outcomes in patients with pancreatic cancer. Full article

(This article belongs to the Special Issue Synthesis of Nanomaterials and Their Applications in Biomedicine)

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12 pages, 3753 KiB

Open AccessArticle

Unveiling the ESIPT Luminescence Mechanism of 4′-N,N-Diethylamino-3-Hydroxyflavone in Ionic Liquid: A Computational Study

by Jin Yang, Qi Li, Meilin Guo, Lu Yan, Lixia Zhu, Jing Zhao, Guangxiong Hu, Hang Yin and Ying Shi

Molecules 2025, 30(6), 1381; https://doi.org/10.3390/molecules30061381 - 20 Mar 2025

Viewed by 350

Abstract

Excited state intramolecular proton transfer (ESIPT) within molecules in solvents plays important roles in photo-chemistry and photo-biology. Herein, the influence of 1-ethyl-3-methyl-imidazolium bis (trifluoromethylsulfonyl) imide ([EMIm][NTf₂]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF₆]) on the ESIPT of 4′-N,N-diethylamino-3-hydroxyflavone (DEAHF) was explored. The [...] Read more.

Excited state intramolecular proton transfer (ESIPT) within molecules in solvents plays important roles in photo-chemistry and photo-biology. Herein, the influence of 1-ethyl-3-methyl-imidazolium bis (trifluoromethylsulfonyl) imide ([EMIm][NTf₂]) and 1-butyl-3-methylimidazolium hexafluorophosphate ([BMIm][PF₆]) on the ESIPT of 4′-N,N-diethylamino-3-hydroxyflavone (DEAHF) was explored. The density functional theory and time-dependent density functional theory methodologies were used. The calculated fluorescence spectrum reveals that the fluorescence peaks of DEAHF in [EMIm][NTf₂] and [BMIm][PF₆] originate from the emission of N* and T* forms. The structure’s optimization, infrared spectra, non-covalent interactions and the scanning of potential energy curves collectively demonstrate that the ESIPT of DEAHF likely happen more in [EMIm][NTf₂] than in [BMIm][PF₆]. The solvation effects in [BMIm][PF₆] exhibit greater prominence compared to those in [EMIm][NTf₂], as evidenced by the free energy curve. The alterations in dipole moment indicate a substantial solvation relaxation during the ESIPT processes. Our aforementioned research offers backing for the advancement of novel fluorescent probes. Full article

(This article belongs to the Special Issue Theoretical Study on Luminescent Properties of Organic Materials)

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21 pages, 5487 KiB

Open AccessReview

Targeting the CXCR4/CXCL12 Axis in Cancer Therapy: Analysis of Recent Advances in the Development of Potential Anticancer Agents

by Gerardina Smaldone, Francesca Di Matteo, Roberta Castelluccio, Valeria Napolitano, Maria Rosaria Miranda, Michele Manfra, Pietro Campiglia and Vincenzo Vestuto

Molecules 2025, 30(6), 1380; https://doi.org/10.3390/molecules30061380 - 20 Mar 2025

Viewed by 1037

Abstract

Cancer, a leading cause of premature death, arises from genetic and epigenetic mutations that transform normal cells into tumor cells, enabling them to proliferate, evade cell death, and stimulate angiogenesis. Recent evidence indicates that chemokines are essential in tumor development, activating receptors that [...] Read more.

Cancer, a leading cause of premature death, arises from genetic and epigenetic mutations that transform normal cells into tumor cells, enabling them to proliferate, evade cell death, and stimulate angiogenesis. Recent evidence indicates that chemokines are essential in tumor development, activating receptors that promote proliferation, invasion, and metastasis. The CXCR4/CXCL12 signaling pathway is gaining attention as a promising target for cancer therapy. CXCR4, a chemokine receptor, is often overexpressed in various types of cancer, including kidney, lung, brain, prostate, breast, pancreas, ovarian, and melanomas. When it binds to its endogenous ligand, CXCL12, it promotes cell survival, proliferation, and migration, crucial mechanisms for the retention of hematopoietic stem cells in the bone marrow and the movement of lymphocytes. The extensive expression of CXCR4 in cancer, coupled with the constant presence of CXCL12 in various organs, drives the activation of this axis, which in turn facilitates angiogenesis, tumor progression, and metastasis. Given the detrimental role of the CXCR4/CXCL12 axis, the search for drugs acting selectively against this protein represents an open challenge. This review aims to summarize the recent advancements in the design and development of CXCR4 antagonists as potential anticancer agents. Full article

(This article belongs to the Special Issue Design, Synthesis and Biological Activity of Novel Antitumor Drugs)

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16 pages, 4935 KiB

Open AccessReview

An Alternative to Biliverdin, Mesobiliverdin IXα and Mesobiliverdin-Enriched Microalgae: A Review on the Production and Applications of Mesobiliverdin-Related Products

by Naveena Poudyal, Jon Y. Takemoto, Yuan-Yu Lin and Cheng-Wei T. Chang

Molecules 2025, 30(6), 1379; https://doi.org/10.3390/molecules30061379 - 19 Mar 2025

Viewed by 396

Abstract

Despite attracting interest for decades due to its anti-inflammatory and antioxidant capabilities, the use of biliverdin IXα (BV) in medicine and agriculture is hampered by uncertain purity and limited availability. A significant amount of effort has been devoted to the production and application [...] Read more.

Despite attracting interest for decades due to its anti-inflammatory and antioxidant capabilities, the use of biliverdin IXα (BV) in medicine and agriculture is hampered by uncertain purity and limited availability. A significant amount of effort has been devoted to the production and application of BV, but with limited success. Mesobiliverdin IXα (MBV), a natural BV analog derived from microalgae, offers a path to overcome the limitations of BV. MBV production is scalable, and it can be obtained at high purity. MBV and BV share important structural features (e.g., bridging propionate groups) and both are substrates of biliverdin reductase A (BVRA), and thus exert the same mechanisms and pathways for anti-inflammatory action. To enable the use of MBV in industry, especially in agriculture, a cost-effective product, mesobiliverdin-enriched microalgae (MEM), was developed. In this review, we focus on recent developments and investigations of MBV and MEM, and compare their effectiveness with BV and Spirulina. This review article highlights cost-effective and scalable production of MEM, the therapeutic potential of MBV in cytoprotection and anti-inflammation, and MEM as an animal feed additive for improved gut health and amelioration of osteoporosis. More studies are ongoing to expand the potential applications of both MBV and MEM from fundamental research to industrial and agricultural practices. Full article

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22 pages, 4475 KiB

Open AccessArticle

Chemical Characterization and Sensory Evaluation of Scottish Malt Spirit Aged in Sherry Casks^®: Comparison Between Static and Dynamic Aging Systems

by Daniel Butrón-Benítez, Manuel J. Valcárcel-Muñoz, M. Valme García-Moreno, M. Carmen Rodríguez-Dodero and Dominico A. Guillén-Sánchez

Molecules 2025, 30(6), 1378; https://doi.org/10.3390/molecules30061378 - 19 Mar 2025

Viewed by 348

Abstract

Aging spirits in wooden casks is a traditional and mandatory process for the production of certain products, such as whisky. The physicochemical and sensory changes that occur during aging are shaped by the characteristics of the barrels and the aging method used. In [...] Read more.

Aging spirits in wooden casks is a traditional and mandatory process for the production of certain products, such as whisky. The physicochemical and sensory changes that occur during aging are shaped by the characteristics of the barrels and the aging method used. In this paper, we examined the behavior of the same malt spirit when aged using two different Sherry Casks^® methods. The first one was static aging, with the distillate remaining still in the cask, and the second one was a dynamic system, characterized by the regular racking of the spirit between casks at different aging stages (Criaderas and Solera). For 36 months, the aging spirits were sampled and analyzed to determine any changes in acidity, volatile, and phenolic compound content that might indicate changes in their chemical profile. The spirits were also subjected to sensory evaluations. The analysis revealed a significant evolution of the distillate in either system, although with different chemical profiles. Multiple Linear Regression Models (MLR and PLS) were successfully used to estimate the age of the distillates at a high level of confidence. Although, after the first racking operation, the distillates in the dynamic system had an average age greater than the theoretical one, these differences tended to fade away as the system gradually stabilized. Full article

(This article belongs to the Section Analytical Chemistry)

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19 pages, 5194 KiB

Open AccessArticle

Structural, Electronic, and Nonlinear Optical Characteristics of Europium-Doped Germanium Anion Nanocluster EuGe_n⁻ (n = 7–20): A Theoretical Investigation

by Chenliang Hao, Xueyan Dong, Chunli Li, Caixia Dong, Zhaofeng Yang and Jucai Yang

Molecules 2025, 30(6), 1377; https://doi.org/10.3390/molecules30061377 - 19 Mar 2025

Cited by 1 | Viewed by 439

Abstract

Doping rare-earth metals into semiconductor germanium clusters can significantly enhance the stability of these clusters while introducing novel and noteworthy optical properties. Herein, a series of EuGe_n⁻ (n = 7–20) clusters and their structural and nonlinear optical properties are investigated [...] Read more.

Doping rare-earth metals into semiconductor germanium clusters can significantly enhance the stability of these clusters while introducing novel and noteworthy optical properties. Herein, a series of EuGe_n⁻ (n = 7–20) clusters and their structural and nonlinear optical properties are investigated via the ABCluster global search technique combined with the double-hybrid density functional theory mPW2PLYP. The structure growth pattern can be divided into two stages: an adsorption structure and a linked structure (when n = 7–10 and n = 11–20, respectively). In addition to simulating the photoelectron spectra of the clusters, their various properties, including their (hyper)polarizability, magnetism, charge transfer, relative stability, and energy gap, are identified. According to our examination, the EuGe₁₃⁻ cluster exhibits a significant nonlinear optical response of the β_tot value of 7.47 × 10⁵ a.u., and is thus considered a promising candidate for outstanding nonlinear optical semiconductor nanomaterials. Full article

(This article belongs to the Special Issue 30th Anniversary of Molecules—Recent Advances in Computational and Theoretical Chemistry)

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11 pages, 5854 KiB

Open AccessArticle

Novel Fe(II)-Based Supramolecular Film Prepared by Interfacial Self-Assembly of an Asymmetric Polypyridine Ligand and Its Electrochromic Performance

by Xiya Chen, Xiaomeng Sun, Tingting Dai, Hongwei Wang, Qian Zhao, Chunxia Yang, Xianchao Du, Xiaojing Xing, Xinfeng Cheng and Dongfang Qiu

Molecules 2025, 30(6), 1376; https://doi.org/10.3390/molecules30061376 - 19 Mar 2025

Cited by 1 | Viewed by 392

Abstract

An asymmetric two-arm polypyridine ligand 4′-{4-[4-(2,2′-dipyridyl)phenyl]}-2,2′:6′,2′-terpyridine (TPY-Ph-BPY) with double coordination units was synthesized using the one-step Suzuki reaction. The metallic supramolecular film was subsequently obtained by the Fe²⁺-induced self-assembly method at the CHCl₃-H₂O interface, which [...] Read more.

An asymmetric two-arm polypyridine ligand 4′-{4-[4-(2,2′-dipyridyl)phenyl]}-2,2′:6′,2′-terpyridine (TPY-Ph-BPY) with double coordination units was synthesized using the one-step Suzuki reaction. The metallic supramolecular film was subsequently obtained by the Fe²⁺-induced self-assembly method at the CHCl₃-H₂O interface, which displayed a distinct flat and continuous morphology. The supramolecular film-coated ITO electrode demonstrated a reversible electrochemical redox behavior with pronounced color changes between purple and light green. Its solid-state electrochromic device had an optical contrast (ΔT%) of 26.2% at λ_max = 573 nm with balanced coloring (t_c = 2.4 s) and bleaching (t_b = 2.6 s) times and a high current efficiency of 507.8 cm²/C. Moreover, good cycling stability with a long-term reversible color change was observed beyond 900 cycles. These results suggested the promising potential of the TPY-Ph-BPY-Fe(II) supramolecular film for electrochromic applications. Full article

(This article belongs to the Special Issue Metal Complexes: Synthesis, Characterization and Applications)

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18 pages, 7329 KiB

Open AccessArticle

Visible-Light Photocatalytic Activity of a ZnO-Loaded Isoreticular Metal-Organic Framework

by Ana Y. Rojas-Forero, Laura Y. Hernández-Benítez, María L. Ospina-Castro, Nataly J. Galán-Freyle, John R. Castro-Suarez, Maximiliano Méndez-López, Samuel P. Hernández-Rivera, José A. Centeno-Ortiz, Sandra P. Romero-Nieto and Leonardo C. Pacheco-Londoño

Molecules 2025, 30(6), 1375; https://doi.org/10.3390/molecules30061375 - 19 Mar 2025

Cited by 1 | Viewed by 465

Abstract

A hybrid material composed of IRMOF-3 and ZnO (IRMOF-3/ZnO) was synthesized to enhance photocatalytic methylene blue (MB) degradation under visible-light irradiation. Scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and diffuse-reflectance UV-Vis analyses confirmed the successful integration of ZnO into the IRMOF-3 framework. [...] Read more.

A hybrid material composed of IRMOF-3 and ZnO (IRMOF-3/ZnO) was synthesized to enhance photocatalytic methylene blue (MB) degradation under visible-light irradiation. Scanning electron microscopy, Fourier-transform infrared spectroscopy, X-ray diffraction, and diffuse-reflectance UV-Vis analyses confirmed the successful integration of ZnO into the IRMOF-3 framework. Compared with unmodified IRMOF-3, the hybrid demonstrated superior MB decomposition, as evidenced by faster reaction rate constants and shorter half-lives. Monitoring the MB absorbance at 670 nm (λ_max) revealed more pronounced colorant removal when IRMOF-3/ZnO was exposed to a visible-light source. Diffuse-reflectance UV-Vis spectroscopy showed that IRMOF-3 has a band gap of 2.7 eV, whereas IRMOF-3/ZnO exhibits a slightly higher band gap of 2.8 eV. This modest shift, coupled with the strong interaction between the ZnO semiconductor and the MOF’s amine functionalities, enabled two distinct energy-transfer pathways: intermolecular transfer from IRMOF-3 linkers (acting as visible-light antennas) to ZnO, and intramolecular transfer from Zn to IRMOF-3. Together, these pathways generated abundant free radicals for efficient dye degradation. Despite the necessity for careful synthesis protocols and control of operating conditions to preserve the MOF structure and optimize ZnO loading, the IRMOF-3/ZnO hybrid shows promise as a robust, cost-effective photocatalyst for water-pollutant remediation, taking advantage of the more abundant visible region of solar light. Full article

(This article belongs to the Special Issue Molecular Spectroscopy in Applied Chemistry)

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14 pages, 3394 KiB

Open AccessArticle

Single-Port Fluorescence Immunoassay for Concurrent Quantification of Live and Dead Bacteria: A Strategy Based on Extracellular Nucleases and DNase I

by Yuhan Wang, Han Dong, Hang Yu, Shaofeng Yuan, Hideya Kawasaki, Yahui Guo and Weirong Yao

Molecules 2025, 30(6), 1374; https://doi.org/10.3390/molecules30061374 - 19 Mar 2025

Viewed by 363

Abstract

Bacteria are the primary culprits of global foodborne diseases, making bacterial detection one of the most critical aspects of food safety. The quantification of viable and dead bacteria is typically achieved through distinct methodologies, such as culture-based methods and molecular biological techniques. These [...] Read more.

Bacteria are the primary culprits of global foodborne diseases, making bacterial detection one of the most critical aspects of food safety. The quantification of viable and dead bacteria is typically achieved through distinct methodologies, such as culture-based methods and molecular biological techniques. These approaches often have non-overlapping requirements in terms of sample pre-treatment and detection equipment. However, in this presented work, bacterial extracellular nucleases and DNase I were utilized to achieve the simultaneous quantification of both live and dead bacteria in a single well of a microplate. The detection limits of the method for live and dead bacteria are estimated to be 7.13 × 10⁵ CFU/mL and 3.54 × 10⁵ CFU/mL, respectively. In the application of detecting bacteria in pickled pork stewed bamboo shoot soup, the detection limit for live bacteria can be reduced to as low as 10² CFU/mL within 24 h after enrichment cultivation. Full article

(This article belongs to the Special Issue Advances in Fluorescence-Based Food Analytical Methods)

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5 pages, 150 KiB

Open AccessEditorial

Editorial: Special Issue “Liquid Crystals II”

by Viorel Cîrcu, Doina Manaila-Maximean and Valery A. Loiko

Molecules 2025, 30(6), 1373; https://doi.org/10.3390/molecules30061373 - 19 Mar 2025

Viewed by 263

Abstract

The Special Issues of the Multidisciplinary Digital Publishing Institute (MDPI) are well-known and highly appreciated in the scientific community [...] Full article

(This article belongs to the Special Issue Liquid Crystals II)

19 pages, 2448 KiB

Open AccessArticle

Cross-Analytical Strategies to Tackle “Medicines in Disguise” Presented as Food Supplements, a New Threat for Human Health

by Judith Nzoughet Kouassi, Chouaha Bouzidi, Béatrice Nicolai, Farah Ben Jamaa, Annabelle Dugay, Jérôme Langrand, Dominique Vodovar, Pascal Houzé, Laurence Labat, Bruno Mégarbane, Cinzia Bocca, Pascal Reynier, Nicolas Guiblin, Sylvie Michel and Xavier Cachet

Molecules 2025, 30(6), 1372; https://doi.org/10.3390/molecules30061372 - 19 Mar 2025

Viewed by 626

Abstract

Plant-based food supplements (FS) of doubtful traceability have now emerged as a new threat to human health. Food supplements adulterated with pharmaceutical ingredients are considered “medicines in disguise” by regulatory authorities, which is a sub-category of falsified medicines. In the context of illegal [...] Read more.

Plant-based food supplements (FS) of doubtful traceability have now emerged as a new threat to human health. Food supplements adulterated with pharmaceutical ingredients are considered “medicines in disguise” by regulatory authorities, which is a sub-category of falsified medicines. In the context of illegal manufacture and trade, as well as in the absence of an official phyto- and/or pharmacovigilance system, emergency departments and poison control centers constitute a early warning system for detecting ingested suspect FS. In the present investigation, we set up efficient workflows for the systematic characterization of adulterated plant-based FS in the context of an original local early warning alert system (i.e., FalsiMedTrack) involving an emergency department, a poison center, and academic analytical chemistry laboratories. Fit-for-purpose cross-analytical methods were employed, including sophisticated methods such as liquid chromatography coupled to high-resolution mass spectrometry, nuclear magnetic resonance, X-ray powder diffraction, as well as the most accessible and affordable HPLC method with UV/DAD detection. The strategy was applied successfully to typical cases of suspect plant-based health products, i.e., sample incriminated in patients experiencing side effects and herbal products currently commercialized for their “amazing health benefits”. The samples contained active pharmaceutical ingredients, including diclofenac, piroxicam, dexamethasone 21-acetate, and sibutramine. We provided evidence of “medicines in disguise” presented as food supplements, which raises concerns about their quality and safety. Full article

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12 pages, 2762 KiB

Open AccessFeature PaperArticle

Ultrasensitive Chemical Analysis on Gold Nano Popcorn Substrate Using Digital Surface-Enhanced Raman Scattering

by Soyeon Lee and Jaebum Choo

Molecules 2025, 30(6), 1371; https://doi.org/10.3390/molecules30061371 - 19 Mar 2025

Viewed by 365

Abstract

This study presents a digital surface-enhanced Raman scattering (SERS) method to enhance the sensitivity of SERS detection for low-concentration analytes. Conventional SERS analysis using average Raman intensity faces limitations in distinguishing low concentrations due to the substrate’s sparse distribution of target molecules. To [...] Read more.

This study presents a digital surface-enhanced Raman scattering (SERS) method to enhance the sensitivity of SERS detection for low-concentration analytes. Conventional SERS analysis using average Raman intensity faces limitations in distinguishing low concentrations due to the substrate’s sparse distribution of target molecules. To overcome this challenge, we used a binary code-based data analysis approach. Gold nano popcorn substrates were utilized for high-sensitivity detection, with malachite green isothiocyanate (MGITC) as the target molecule. Raman mapping data were analyzed using both the conventional average Raman intensity method and the proposed digital SERS approach. In the digital SERS method, a threshold value was established based on the mean and standard deviation of Raman signals in the absence of target molecules. Pixels with Raman intensities exceeding this threshold were assigned a value of “1”, while those below were assigned “0”. Quantification was then performed based on these digital counts corresponding to MGITC concentrations. Our results demonstrate that the digital SERS method significantly improved the ability to distinguish and quantify analytes in low-concentration ranges that were indiscernible using the conventional approach. This analytical technique shows promise for ultrasensitive chemical analysis and expands the capabilities of SERS-based detection methods, potentially revolutionizing the field of trace analyte detection. Full article

(This article belongs to the Special Issue From Spectroscopic Insights to Structural Wonders: A Theme Issue Dedicated to Professor Jaan Laane)

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12 pages, 705 KiB

Open AccessArticle

Scaptotrigona mexicana Propolis from Totonacapan Region: Chemical Composition, Antioxidant and Antibacterial Activities

by Blanca E. Rivero-Cruz, Maria Ema Rojas-Brandao, Adriana Correa-Benítez, Ingeborg Becker, Aurora Xolalpa-Aroche, José Delgado-Dominguez and J. Fausto Rivero-Cruz

Molecules 2025, 30(6), 1370; https://doi.org/10.3390/molecules30061370 - 19 Mar 2025

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Abstract

The propolis produced by stingless bees is a complex mixture of natural sticky components mixed with soil or clay. Global research on propolis has focused on studying the biological and pharmacological properties and chemical composition of stingless bee propolis from Brazil, Indonesia, and [...] Read more.

The propolis produced by stingless bees is a complex mixture of natural sticky components mixed with soil or clay. Global research on propolis has focused on studying the biological and pharmacological properties and chemical composition of stingless bee propolis from Brazil, Indonesia, and other regions. However, studies of stingless bee propolis produced in Mexico are scarce. This study aimed to determine the chemical composition of the geopropolis of Scaptotrigona mexicana collected in the Totonacapan region and to evaluate its antioxidant and antibacterial activities. The phenolic contents of the ethanolic extract of the collected propolis ranged from 2.45 ± 0.03 mg GAE/g to 3.48 ± 0.56 mg GAE/g of dry extract. The total flavonoid content ranged from 0.69 ± 0.03 mg QE/g to 0.84 ± 0.009 mg QE/g of dry extract. The antioxidant activity of the ethanolic extracts was assessed via DPPH, ABTS, and FRAP assays. The minimum inhibitory concentration values exhibited by the ethanolic extract (>512 g/mL) for Gram-negative bacteria (Pseudomonas aerugunosa and Phorphyromonas gingivalis) were higher than those of Gram-positive bacteria. The stingless bee propolis extract showed the highest antibacterial activity against Streptococcus mutans (256 g/mL). Five known compounds, taraxeryl acetate (1), lupeol (3), cicloart-23-en-3β,25-diol (5), mangiferoic acid (6), and 5-(11’Z-heptadecenyl)-resorcinol (7), and two irresoluble mixtures of 3-O-acetyl-α-(2a) and 3-O-acetyl-β-amyrins (2b), and α- (4a) and -amyrins (4b), were identified by nuclear magnetic resonance spectroscopy and mass spectrometry. Additionally, 39 volatile compounds were identified via headspace-solid phase microextraction using the hyphenated gas chromatography coupled to mass spectrometry time-of-flight. The main volatile compounds detected include trans-α-bergamotene (8.15%), hexanal (7.17%), 2-heptanone (7.60%), and α-copaene (7.09%). Full article

(This article belongs to the Section Natural Products Chemistry)

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19 pages, 8471 KiB

Open AccessArticle

Green Nanoparticle Synthesis in the Application of Non-Bacterial Mastitis in Cattle

by Michał Motrenko, Agata Lange, Aleksandra Kalińska, Marcin Gołębiewski, Małgorzata Kunowska-Slósarz, Barbara Nasiłowska, Joanna Czwartos, Wojciech Skrzeczanowski, Aleksandra Orzeszko-Rywka, Tomasz Jagielski, Anna Hotowy, Mateusz Wierzbicki and Sławomir Jaworski

Molecules 2025, 30(6), 1369; https://doi.org/10.3390/molecules30061369 - 18 Mar 2025

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Abstract

This study explores the potential of silver nanoparticles (AgNPs) synthesized through an eco-friendly method using coffee extract to combat non-bacterial mastitis in dairy cattle. Mastitis, often caused by pathogens such as yeasts and algae like Prototheca spp., poses a challenge due to the [...] Read more.

This study explores the potential of silver nanoparticles (AgNPs) synthesized through an eco-friendly method using coffee extract to combat non-bacterial mastitis in dairy cattle. Mastitis, often caused by pathogens such as yeasts and algae like Prototheca spp., poses a challenge due to the limited efficacy of traditional antibiotics. This research utilized strains isolated from mastitis milk and assessed the nanoparticles’ physicochemical properties, antimicrobial efficacy, and impact on biofilm formation and microorganism invasion. AgNPs demonstrated a spherical shape with a mean hydrodynamic diameter of ~87 nm and moderate colloidal stability. Antimicrobial tests revealed significant growth inhibition of yeast and Prototheca spp., with minimal inhibitory concentrations (MICs) as low as 10 mg/L for certain strains. Biofilm formation was notably disrupted, and microorganism invasion in bioprinted gels was significantly reduced, indicating the broad-spectrum potential of AgNPs. The study highlights the nanoparticles’ ability to damage cell membranes and inhibit metabolic activities, presenting a promising alternative for managing infections resistant to conventional treatments. These findings suggest that green-synthesized AgNPs could play a pivotal role in developing sustainable solutions for mastitis treatment, particularly for pathogens with limited treatment options. Full article

(This article belongs to the Special Issue Advanced Functional Nanomaterials in Medicine and Health Care)

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11 pages, 2538 KiB

Open AccessArticle

Isolation, Chemical Characterization, and Antimicrobial Activity of Secondary Metabolites from Pseudocyphellaria faveolata

by Cecilia Rubio, Javiera Ramírez, Caroline Weinstein-Oppenheimer, Tania F. Bahamondez-Canas and Natalia Quiñones

Molecules 2025, 30(6), 1368; https://doi.org/10.3390/molecules30061368 - 18 Mar 2025

Viewed by 374

Abstract

Introduction: Antimicrobial resistance is a global threat, highlighting the urgent need for novel antimicrobial agents. Among the mechanisms of resistance, bacteria can release drug-degrading enzymes and express efflux pumps, as well as grow in protected aggregates known as biofilms. Pseudomonas aeruginosa and Staphylococcus [...] Read more.

Introduction: Antimicrobial resistance is a global threat, highlighting the urgent need for novel antimicrobial agents. Among the mechanisms of resistance, bacteria can release drug-degrading enzymes and express efflux pumps, as well as grow in protected aggregates known as biofilms. Pseudomonas aeruginosa and Staphylococcus aureus are among the most prevalent biofilm infections in chronic wounds, respiratory and urinary tract infections, and device-associated infections. Pseudocyphellaria faveolata (Delise) Malme is a lichen with metabolites with unexplored antimicrobial potential. Aims: To identify and characterize the major metabolites present in Pseudocyphellaria Faveolata and to determine their antimicrobial activity against Staphylococcus aureus and Pseudomonas aeruginosa. Methods: The molecules were purified by column chromatography and characterized by NMR spectroscopy. The antimicrobial activity of the compounds was determined in terms of proliferation, adhesion, and viability against P. aeruginosa and S. aureus by the broth microdilution method and crystal violet staining. Viability was determined by the resazurin reduction assay on normal human fibroblasts to determine cytotoxicity over human cells. Results: The major metabolites were spectroscopically characterized and identified as physciosporin and methyl virensate. Physciosporin showed antimicrobial activity on S. aureus, with a MIC of 32 μg/mL and MBC of 128 μg/mL, and prevented biofilm formation from 16 μg/mL. Methyl virensate also had antimicrobial activity on S. aureus (MIC = 64 μg/mL). None of these metabolites significantly affected P. aeruginosa proliferation, viability, or adhesion. Cytotoxicity of physciosporin at 16 ug/mL on normal human fibroblasts was below 20%. Conclusions: This is the first report on the study of the antimicrobial activity of these compounds. Physciosporin showed promising activity in preventing the formation of S. aureus biofilms, which are responsible for chronic infections. These findings provide a foundation for exploring the antimicrobial potential of other lichenic depsidones. Full article

(This article belongs to the Section Natural Products Chemistry)

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21 pages, 2101 KiB

Open AccessArticle

Straightforward Superbase-Mediated Reductive O-Phosphorylation of Aromatic and Heteroaromatic Ketones with Red Phosphorus in the Superbase Suspension KOH/DMSO(H₂O)

by Vladimir A. Kuimov, Svetlana F. Malysheva, Natalia A. Belogorlova, Ruslan I. Fattakhov, Alexander I. Albanov, Irina Yu. Bagryanskaya, Nikolay I. Tikhonov and Boris A. Trofimov

Molecules 2025, 30(6), 1367; https://doi.org/10.3390/molecules30061367 - 18 Mar 2025

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Abstract

It was shown for the first time that diaryl(hetaryl)ketones are capable of directly phosphorylating with red phosphorus in the superbase suspension KOH/DMSO(H₂O) at 85 °C for 1.5 h to afford potassium bis(diaryl(hetaryl)methyl)phosphates that were earlier inaccessible in a yield of up [...] Read more.

It was shown for the first time that diaryl(hetaryl)ketones are capable of directly phosphorylating with red phosphorus in the superbase suspension KOH/DMSO(H₂O) at 85 °C for 1.5 h to afford potassium bis(diaryl(hetaryl)methyl)phosphates that were earlier inaccessible in a yield of up to 45%. The ESR data demonstrate that unlike previously published phosphorylation with elemental phosphorus, this new phosphorylation reaction proceeds via a single electron transfer from polyphospide anions to diaryl(hetaryl)ketones. This is the first example of the C-O-P bond generation during the phosphorylation with elemental phosphorus in strongly basic media, which usually provides C-P bond formation. Full article

(This article belongs to the Special Issue Exclusive Contributions by the Editorial Board Members (EBMs) of the Organic Chemistry Section of Molecules)

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